Taxiing past the Pinwheel helicopter (see photo 678360) at Van Nuys. This airport was used by the USAF until 1990. The old Mitchell was one of a 1000-aircraft batch from fiscal year 1944. The tail number system requires the first digit of the full serial to be omitted. When in 1954 someone observed that 1940s and 1950s planes with the same tail numbers were in active service, this was curiously addressed not by simply adding the 'decade digit', but by introding a 0 (not O) prefix for older aircraft. See the article in our AirHistory Magazine section. Photo by: Ralph Crane / Life

The photographer framed the Pinwheel helicopter (see photo 678360) with this S-51 of the US Forest Service. Other shots show the reg clearly as N155Z but it's not listed by the FAA or anywhere else. From 1960 N155Z was worn by a C-46 Commando that the FAA has also forgotten about. Photo by: Ralph Crane / Life

Half man, half helicopter. This 'strap-on helicopter' was powered by rocket motors mounted at the rotor tips. The tail rotor was for steering. Tested by the US Navy against the Hiller ROE and Gyrodyne RON but RH-1 does not seem to be a naval designation and nor is a serial known. Photo by: Ralph Crane / Life

After flying for Eastern and Mackey International Airlines, this airframe served with several operators in Bolivia from 1980 as CP-1574. It was reportedly broken up in the late 1990s. Photo from: Convair

Withdrawn from use in 1964. Photo from: Whites Aviation Collection/Alexander Turnbull Library

Airwork Limited operated this 1947-built Viking 1B between 10.54 and 02.58.